The　sulfonated　phthalimidomethyl　phthalocyanine　hydroxyl　aluminum　(Al(OH)PcSP)　is　an　amphiphilic　photosensitizer　which　was　proved　to　have　the　photodynamic　activities　against　cancer.　The　electronic　absorption　spectra　and　aggregation　state　of　the　Al　(OH)PcSP　in　aqueous　alcoholic　solutions　and　water　were　investigated.　The　results　showed　that　the　Al(OH)　PcSP　existed　in　the　form　of　monomer　in　aqueous　alcoholic　solutions.　The　increase　in　the　carbon　chain　and　hydroxy　of　alcohol　in　solutions　had　no　significant　effects　on　the　absorption　spectra　behaviors　of　Al(OH)　PcSP.　But　in　water,　the　Al(OH)　PcSP　existed　in　the　equilibrium　between　monomer　and　dimer.　The　dimerization　constant　was　5.730　7　x　10(4)　mol(-1).L.　The　characteristic　absorption　peak　of　the　Q　band　of　the　Al(OH)PcSP　dimer　was　red　shifted　to　740.5　nm　from　that　of　the　monomer　(676.5　nm),which　contrast　with　those　of　other　metal　phthalocyanines　dimer.　The　study　on　the　fluorescence　spectra　of　Al(OH)PcSP　in　aqueous　alcoholic　solutions　suggested　that　the　fluorescence　of　the　dimer　was　weak.